From a30debae054b851bb85d8e0ef9c9bd6e87475662 Mon Sep 17 00:00:00 2001 From: nathanw Date: Sat, 6 Jan 2001 17:16:19 +0000 Subject: [PATCH] Add description of the pinout of a standard DB-25 parallel port, relative to the bits described here. --- sys/dev/ic/lptreg.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/sys/dev/ic/lptreg.h b/sys/dev/ic/lptreg.h index 40bbc0737bc8..d49ad756dfe9 100644 --- a/sys/dev/ic/lptreg.h +++ b/sys/dev/ic/lptreg.h @@ -1,4 +1,4 @@ -/* $NetBSD: lptreg.h,v 1.5 1996/11/23 23:22:50 cgd Exp $ */ +/* $NetBSD: lptreg.h,v 1.6 2001/01/06 17:16:19 nathanw Exp $ */ /*- * Copyright (c) 1990 The Regents of the University of California. @@ -45,6 +45,20 @@ * Copyright (C) William Jolitz 1990 */ +/* + * On a standard DB25 parallel port, the bits show up as follows: + * + * 13 12 11 10 9 8 7 6 5 4 3 2 1 + * ~S7 S6 S5 S4 D7 D6 D5 D4 D3 D2 D1 D0 ~C0 + * + * G G G G G G G G ~C3 C2 S3 ~C1 + * 25 24 23 22 21 20 19 18 17 16 15 14 + * + * D7-D0 are output bits from the data register + * S7-S3 are input bits read at the status register + * C3-C0 are output bits from the control register + */ + #define lpt_data 0 /* Data to/from printer (R/W) */ #define lpt_status 1 /* Status of printer (R) */